Quick answer: Dry eye in dogs — keratoconjunctivitis sicca (KCS) — means the tear glands stop producing enough of the watery part of the tear film, so the cornea dries out and the eye compensates with thick, sticky mucus. It is diagnosed with a one-minute Schirmer tear test and, in most dogs, is a lifelong immune-mediated condition managed with prescription tear-stimulating drops. English Bulldogs carry 38 times the odds of a crossbred dog. No rinse, wipe, or home remedy fixes it — but it is very treatable once correctly identified. Alongside prescribed therapy, a non-medicated dog eye cleaning rinse (isotonic, pH 7.0–7.2, filtered to 10 microns) is only for clearing accumulated mucus and debris — never a substitute for the drops your vet prescribes.
The frustrating part is how ordinary it looks at the start — a little goopy discharge, a dull eye, slightly more blinking. Plenty of owners clean it away for months and only learn the real cause once the cornea has started to change.
What dry eye in dogs actually is
A healthy tear film has three layers: oil from the meibomian glands, water from the lacrimal and third-eyelid glands, and an inner mucin layer. Dry eye is a failure of the watery layer, and in most dogs the cause is immune-mediated — the immune system gradually destroys lacrimal gland tissue, which is why the condition appears in middle age and progresses rather than resolves.
Two things then happen at once. The cornea loses its lubrication and becomes irritated, inflamed, and vulnerable to ulcers. And the mucin-producing cells go into overdrive compensating — which is why the hallmark sign of dry eye is not a dry-looking eye but a stubbornly gooey one.
Signs of dry eye in dogs
The pattern matters more than any single sign: dry eye is chronic, usually affects both eyes (not always equally), and returns no matter how often you clean it.
| Sign | What it looks like | Stage |
|---|---|---|
| Thick, ropy, gray-green mucus | Sticky strands that reform within hours of cleaning | Early and ongoing |
| Dull, lusterless cornea | The eye loses its wet “shine,” especially at the center | Early |
| Red, thickened conjunctiva | Persistent pink around the white of the eye | Early to moderate |
| Squinting, pawing, light sensitivity | Signs of genuine corneal pain | Moderate |
| Corneal pigment and blood vessels | Brown or dark discoloration creeping in from the edge | Advanced — vision-threatening |
| Corneal ulcer | Sudden pain, cloudiness, held-shut eye | Emergency |
That gray-green mucus is the most misread sign in the condition. Owners interpret it as pus and assume infection, when it is really the tear film's mucin layer without enough water to thin it out. If your dog's discharge is green or yellow, our guide to green discharge eye dog explains how to tell them apart, and the warning signs of a dog eye infection are worth reviewing too — dry eye and secondary bacterial conjunctivitis frequently travel together. If the surface has gone hazy rather than merely dull, read our guide to blue cloudy dog eyes, because untreated dry eye is one of the routes to a corneal ulcer.
Which dogs are most at risk
The largest primary-care study analyzed 363,898 UK dogs and found KCS in 0.40% (O'Neill et al., Journal of Small Animal Practice, 2021). That sounds low until you read the breed numbers.
| Breed | Odds vs crossbred dogs | Practical takeaway |
|---|---|---|
| American Cocker Spaniel | 52× | Annual Schirmer test from middle age |
| English Bulldog | 38× | Highest-risk brachycephalic breed — see below |
| Pug | 22× | Watch for central corneal pigment, not just discharge |
| Lhasa Apso | ~22× | Long facial hair hides early discharge |
| All brachycephalic breeds | 3.63× vs mesocephalic | Flat face is an independent risk factor |
| All spaniels | 3.03× vs non-spaniels | Risk rises steadily with age |
Bulldog dry eye: why the standard test can miss it
This is the part most articles leave out, and it changes what you should ask for at the appointment. In a flat-faced dog, dry eye is frequently not a tear-production problem at all. It is a tear-retention problem — and a Schirmer strip only measures production.
Bulldogs, Pugs, Shih Tzus, Boston Terriers and Pekingese have shallow orbits, prominent globes and often eyelids that do not fully meet. Lagophthalmos — incomplete eyelid closure — is documented in 82% of Shih Tzu eyes, with a mean 15% gap remaining at the end of a blink, and in that same cohort the median Schirmer value was 25.0 mm/min: comfortably normal. Yet those eyes showed measurable tear-film instability (Vitor et al., Acta Veterinaria Scandinavica, 2024, 28 dogs). Normal tear volume, abnormal ocular surface. A test result of “22 mm, all fine” in a Bulldog does not close the question.
Two more findings compound it. Aqueous tear secretion measured by Schirmer test runs roughly 14% lower in brachycephalic dogs than in non-brachycephalic dogs without any ocular complaint, and corneal sensitivity is reduced — nerve density is lowest at the centre of the cornea, exactly where the exposure damage lands. Because of that shift, brachycephalic dogs with readings of 12–13 mm/min plus clinical signs are considered candidates for medical therapy, rather than the usual sub-10 threshold (Plummer, Today's Veterinary Practice, 2026, brachycephalic ocular syndrome review).
Put together: a Bulldog can score “normal” on the one test everyone runs, feel nothing while the centre of the cornea dries out because it has less sensation there, and present months later with pigment already laid down. What to ask for instead of a bare Schirmer number: a tear film break-up time, an assessment of blink completeness, and a fluorescein stain. Flat-faced dogs also show other surface-protection problems that look alarming but are separate issues, such as a dog third eyelid showing across the corner of the eye.
Three less common routes to the same endpoint
- Drug-induced. Sulfonamide antibiotics and etodolac can reduce tear production, sometimes reversibly if caught early — an argument for tear testing dogs on long-term sulfa drugs.
- Neurogenic. When the nerve supply to the tear gland is disrupted, one eye goes dry — and so does the nostril on the same side. In a Zurich series of 11 dogs, that pairing came with a mean Schirmer value of 1.9 mm/min, was usually idiopathic, and several dogs responded to oral pilocarpine (Matheis et al., Veterinary Ophthalmology, 2012). Mention a crusty nose to your vet; it changes the treatment.
- Congenital alacrima. Puppies born with underdeveloped tear glands. Yorkshire Terriers are significantly overrepresented and respond poorly to standard therapy, so the prognosis is guarded (Westermeyer et al., Veterinary Ophthalmology, 2009).
How dry eye is diagnosed
The Schirmer tear test takes one minute. A calibrated paper strip is tucked into the lower eyelid and the vet reads how far the tears wick along it. Normal canine values are generally above 15 mm/min; readings below 10 mm/min with matching clinical signs support a diagnosis, and below 5 mm/min is considered severe. It is usually paired with a fluorescein stain to check for the corneal ulcers dry eyes are prone to.
No home test substitutes for this — you cannot judge tear volume by looking, because the visible wetness on a dry eye is mucus, not tears. In a predisposed breed, ask for a Schirmer test at the annual exam; the study authors recommended exactly that. In a flat-faced breed, ask for the break-up time as well, for the reason set out above.
Treatment: what actually works
Topical immunomodulators are the backbone of therapy. Cyclosporine ophthalmic ointment is the long-established first-line drug, with tacrolimus as an alternative or step-up. They calm the immune attack on the lacrimal gland so it can resume producing tears — treating the cause, not just the symptom.
The classic study of 36 dogs found topical cyclosporine raised tear production by 5 mm/min or more in every dog starting above 2 mm/min, and in 59% of eyes starting at 0–2 mm/min. It also reversed chronic corneal pigment and vessel growth, even where tear production never improved (Kaswan et al., Archives of Ophthalmology, 1989).
The catch: this is lifelong management, not a cure. When UC Davis researchers withdrew immunomodulator treatment from 14 well-controlled dogs, half the eyes fell from a mean Schirmer value of 15.9 mm/min to 6.1 mm/min, taking about three weeks to drop below the 10 mm/min threshold (Park et al., Journal of Ocular Pharmacology and Therapeutics, 2021). Stopping because the eye “looks better” is how dogs relapse. Artificial tears help with comfort but do nothing to restore gland function.
Where daily eye hygiene fits
The honest version, because a lot of marketing gets this wrong: no rinse, wipe, or supplement treats keratoconjunctivitis sicca. Prescription cyclosporine or tacrolimus does that, and nothing on this page replaces it. What careful daily hygiene does is clear the mucus that accumulates between doses, so medication reaches the corneal surface instead of sitting on a crust and trapped debris does not abrade a fragile cornea.
For that job the fluid matters. Our dog eye cleaning rinse is formulated at pH 7.0–7.2, matching the natural tear film, and is isotonic and sterile-filtered to 10 microns, so it does not sting an inflamed eye. It carries sodium hyaluronate at 0.05% — the water-binding molecule used in ophthalmic lubricants — with no alcohol, bleaching agents, or added fragrance. To be explicit: it is a non-medicated hygiene rinse, not therapeutic artificial tears and not a treatment for KCS, and it is used in addition to — never instead of — the drops your veterinarian prescribes. Technique matters as much as the fluid, so it is worth reading how to clean around your dog's eyes properly, and what the shelf-bought alternatives can and cannot do in our look at over-the-counter eye drops for dogs.
The same caveat applies if you are weighing up daily antioxidant support: Advanced Vision drops for dogs is maintenance for an aging dog's eyes, dosed to body weight, not a treatment for a diagnosed tear-film disorder. It is made in North America in a GMP facility, carries a certificate of analysis on every batch, and ships free worldwide. If you are comparing options, our review of the best eye supplement for dogs sets out what the canine evidence supports and what it does not. Our dog eye health guide covers the full routine, alongside the rest of our dog eye care supplements.
Four mistakes that cost dogs vision
- Treating recurring discharge as a cleaning problem. Wiping the same eye clean every day for weeks is a diagnostic finding, not a chore. Book the tear test.
- Accepting a normal Schirmer in a flat-faced dog as the end of the conversation. See the Bulldog section above — production can be normal while the film still fails.
- Reaching for human redness-relief drops. Tetrahydrozoline and naphazoline constrict blood vessels and mask inflammation without addressing it; they are not appropriate for dogs.
- Using leftover steroid eye medication. On an ulcerated cornea — a real risk in any dry eye — topical steroids can accelerate damage badly. Nothing steroidal goes in without a fresh fluorescein stain.
- Stopping treatment once the eye looks good. The eye looks good because of the treatment. See the withdrawal data above.
When to call your vet today
Same-day appointment if your dog is squinting or holding the eye shut, if the eye looks cloudy or hazy, if pain increases suddenly, or if the discharge changes character abruptly. Any of these can signal a corneal ulcer, which in a dry eye deteriorates fast. Persistent redness alone also deserves a look — our guide to why your dog's eyes are red walks through the differential, and if my dog is squinting in one eye describes what you are seeing, that guide covers the first-hour response.
Frequently asked questions
Are Bulldogs prone to dry eye?
Yes. English Bulldogs carried 38 times the odds of KCS compared with crossbred dogs in a study of 363,898 UK dogs, and brachycephalic breeds overall carried 3.63 times the odds of mesocephalic breeds. Flat-faced dogs also lose tears faster through incomplete blinking, so a Bulldog can show dry-eye damage with a Schirmer reading that reads as normal.
Can dry eye in dogs be cured?
Immune-mediated KCS is managed rather than cured. Most dogs need topical immunomodulator therapy for life, and tear production typically declines again within weeks if it is discontinued. Some drug-induced and neurogenic cases can resolve when the underlying cause is addressed.
Can I use human artificial tears on my dog?
Veterinarians sometimes suggest plain preservative-free lubricant drops as a comfort measure, but they do not increase tear production and are not a substitute for prescription therapy. Ask before adding anything, and avoid any human product marketed for redness relief.
Is dry eye painful for dogs?
Yes. The cornea is densely innervated, so a poorly lubricated one is genuinely uncomfortable — hence the blinking, face-pawing, and light sensitivity. Corneal sensitivity is reduced in brachycephalic breeds, which is why those dogs sometimes show damage before they show discomfort. Comfort usually improves within weeks of appropriate treatment.
Scientific References
- O'Neill DG, Brodbelt DC, Keddy A, Church DB, Sanchez RF. Keratoconjunctivitis sicca in dogs under primary veterinary care in the UK: an epidemiological study. Journal of Small Animal Practice. 2021;62(8):636–645. PMID: 34134171. PubMed
- Vitor RC, Teixeira JBC, Santos KC, et al. Shih-Tzu dogs show alterations in ocular surface homeostasis despite adequate aqueous tear production. Acta Veterinaria Scandinavica. 2024;66:1. doi:10.1186/s13028-024-00724-2. PMID: 38229091. PubMed
- Plummer CE. Understanding and Addressing Brachycephalic Ocular Syndrome. Today's Veterinary Practice. 2026. todaysveterinarypractice.com
- Kaswan RL, Salisbury MA, Ward DA. Spontaneous canine keratoconjunctivitis sicca. A useful model for human keratoconjunctivitis sicca: treatment with cyclosporine eye drops. Archives of Ophthalmology. 1989;107(8):1210–1216. PMID: 2757551. PubMed
- Park SA, Good KL, Thomasy SM, Kass PH, Murphy CJ. Effect of withdrawing chronic topical immune modulating treatment on Schirmer tear test values in dogs with dry eye disease. Journal of Ocular Pharmacology and Therapeutics. 2021;37(7):394–398. PMID: 34232790. PubMed
- Matheis FL, Walser-Reinhardt L, Spiess BM. Canine neurogenic keratoconjunctivitis sicca: 11 cases (2006–2010). Veterinary Ophthalmology. 2012;15(4):288–290. PMID: 22051024. PubMed
- Westermeyer HD, Ward DA, Abrams K. Breed predisposition to congenital alacrima in dogs. Veterinary Ophthalmology. 2009;12(1):1–5. PMID: 19152591. PubMed
- Cornell University College of Veterinary Medicine, Riney Canine Health Center. Keratoconjunctivitis sicca (KCS) in dogs. vet.cornell.edu
Veterinary disclaimer: This article is for general educational purposes and does not constitute veterinary advice, diagnosis, or treatment. Dry eye is a progressive condition that can threaten vision. Always consult a licensed veterinarian about your dog's eyes before starting, stopping, or changing any product or medication. Pure Majesty Pets products are grooming and nutritional supplements; they are not drugs and are not intended to diagnose, treat, cure, or prevent any disease.